ascorbic-acid and Leukemia--Myeloid

1. Low serum B12 levels can be measured with considerable precision by microbiological assay with the Euglena gracilis assay and B12 deficiency can be recognised with a high level of consistency by either the Euglena or L. leichmannii assays. Either method is ideally suited for the assay of large numbers of specimens. The Lactobacillus leichmanii technique requires preliminary extraction of protein and it has been suggested that this may be a source of inaccuracy. 2. The radioisotope dilution assay should be the ideal method of measuring B12 levels in small or moderate numbers of specimens for it is a simple method that can be carried out in any laboratory with suitable counting equipment. After many false starts the conditions required for accurate assay are now understood. Each of 40 to 50 radioisotopic dilution techniques that have been introduced claims to be capable of differentiating B12 deficiency from control subjects but the reported correlations between the actual levels found in the two different assays are variable and the levels may be much higher with some radioisotopic methods. 3. The subnormal serum levels which are found in pernicious anaemia with all these techniques indicate severe reduction of the liver B12 level. A low serum B12 level in other conditions has, in the absence of associated folate or iron deficiency, the same significance. If the fall in the serum B12 level is associated with folate or iron deficiency, the tissue B12 levels are usually reduced but not to the low levels found in B12 deficiency states. 4. In practice, a subnormal B12 level is a valuable pointer not only to unsuspected pernicious anaemia but also to other gastrointestinal or nutritional disorders. The significance of a fall in the B12 level can only be understood if its cause is defined by a full clinical and gastroenterological investigation. 5. Falsely low serum B12 levels are found under certain iatrogenic conditions and B12 levels may be normal in spite of cellular deficiency of B12 under the rare circumstances of pernicious anaemia being associated with chronic myeloid leukaemia or when there is deficiency of TC 2.

Topics: Anemia, Megaloblastic; Anemia, Pernicious; Ascorbic Acid; Biological Assay; Bone Marrow; Bone Marrow Cells; Carrier Proteins; Deoxyuridine; Euglena gracilis; Female; Folic Acid Deficiency; Humans; Intrinsic Factor; Lactobacillus; Leukemia, Myeloid; Male; Pregnancy; Pregnancy Complications; Radioisotope Dilution Technique; Transcobalamins; Vitamin B 12; Vitamin B 12 Deficiency

Patients with haematological malignancies are often vitamin C deficient, and vitamin C is essential for the TET-induced conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), the first step in active DNA demethylation. Here, we investigate whether oral vitamin C supplementation can correct vitamin C deficiency and affect the 5hmC/5mC ratio in patients with myeloid cancers treated with DNA methyltransferase inhibitors (DNMTis).. Normalization of plasma vitamin C by oral supplementation leads to an increase in the 5hmC/5mC ratio compared to placebo-treated patients and may enhance the biological effects of DNMTis. The clinical efficacy of oral vitamin C supplementation to DNMTis should be investigated in a large randomized, placebo-controlled clinical trial.. ClinicalTrials.gov, NCT02877277 . Registered on 9 August 2016, retrospectively registered.

Topics: Administration, Oral; Aged; Aged, 80 and over; Ascorbic Acid; Azacitidine; CpG Islands; Denmark; DNA Methylation; Double-Blind Method; Epigenesis, Genetic; Female; Humans; Leukemia, Myeloid; Male; Middle Aged; Myelodysplastic Syndromes; Pilot Projects

A nutrient mixture (NM) containing ascorbic acid, lysine, proline and green tea extract has exhibited anticancer activity in vitro and in vivo in a number of cancer cell lines. We investigated the effect of NM on human leukemic myeloid U-937 cells in vitro by measuring: cell proliferation, MMP expression, invasion, apoptosis, and COX-2 and COX-1 protein expression.. Human leukemic cell line U-937 (ATCC) was cultured in RPMI medium supplemented with fetal bovine serum and antibiotics. After 24 h, the cells were treated with NM at 0, 50, 100, 250, 500 and 1000 Ојg/ml, in triplicate at each dose. Phorbol 12-myristate 13-acetate (PMA), 100 ng/ml was added to cells to induce MMP-9 secretion. Cell proliferation was evaluated by MTT assay, MMP expression by gelatinase zymography, invasion through Matrigel, apoptosis by using live green caspase detection kit (Molecular Probe), and COX-2 and COX-1 expression by Western blot.. NM had no effect on U-937 cell growth at a concentration of 250 Ојg/ml and exhibited an antiproliferative effect at 500 Ојg/ml concentration. Zymography did not demonstrate MMP-2 or MMP-9 secretion in normal cells; however, PMA strongly induced MMP-9, which was inhibited by NM in a dose-dependent manner. Cell penetration through Matrigel was significantly reduced (by 95%) at 250 Ојg/ml NM and completely blocked at 500 Ојg/ml NM. NM induced slight apoptosis at 100 Ојg/ml and moderate at 500 and 1000 Ојg/ml concentration. NM inhibited COX-2 expression in a dose-dependent fashion and had no effect on COX-1 expression.. Our results suggest that NM has potent inhibitory effects on U-937 cell growth and expression of inflammatory mediators, significant parameters in AML progression.

Topics: Antineoplastic Agents; Apoptosis; Ascorbic Acid; Camellia sinensis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Humans; Inflammation Mediators; Leukemia, Myeloid; Lysine; Plant Extracts; Proline; Prostaglandin-Endoperoxide Synthases

We showed previously that homocysteine thiolactone (HcyT) is a potent inducer of apoptosis in HL-60 cells. In the present study, the role of some radical scavengers (N-acetylcysteine, vitamin C, vitamin E and folate) on the reduction of HcyT-induced apoptosis was investigated. Preincubation of HcyT-treated HL-60 cells with vitamin C (Vit C; 100 micro mol/L) or vitamin E (Vit E; 100 micro mol/L) for 2 h significantly reduced the proportion of apoptotic cells with hypodiploid DNA contents or with membrane phosphatidylserine exposure, and attenuated the apoptotic DNA fragmentation. Preincubation of cells with N-acetylcysteine (NAC; 5 mmol/L) for 2 h significantly reduced HcyT-promoted apoptosis measured by membrane phosphatidylserine exposure only. The reduction of HcyT-induced apoptosis by NAC, Vit C or Vit E occurred simultaneously with a significant decrease in intracellular H(2)O(2) levels and reduced caspase-3 enzymatic activity. In contrast, folate had no H(2)O(2) scavenging capacity and did not suppress caspase-3 activity 6 h after HcyT treatment, although folate exhibited antioxidant behavior toward superoxide anions, hydroxyl radicals and peroxynitrite. Preincubation of cells with folate (10 micro mol/L) for 3 d did not affect the extent of HcyT-promoted apoptotic damage. Taken together, our findings suggest that antioxidant pretreatment with NAC, Vit C or Vit E exerts more beneficial effects than folate on reducing apoptotic cell damage induced by homocysteine thiolactone.

Topics: Acetylcysteine; Antioxidants; Apoptosis; Ascorbic Acid; Folic Acid; HL-60 Cells; Homocysteine; Humans; Hydrogen Peroxide; Leukemia, Myeloid; Vitamin E

Arsenic trioxide (As2O3) induces remission in a high proportion of patients with acute promyelocytic leukaemia (APL) via induction of apoptosis. Preliminary reports suggest that the apoptotic effect of As2O3 is not specific for APL but can also be observed in non-APL acute myeloid leukaemia (AML) cells, although these are less sensitive than APL cells. Ascorbic acid has recently been demonstrated to enhance the apoptotic effect of As2O3. We have therefore evaluated combined As2O3/ascorbic acid treatment in various clinical samples of AML. Our results indicate a significant synergistic effect of As2O3 and ascorbic acid, suggesting a possible future role of As2O3/ascorbic acid combination therapy in patients with AML.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Antioxidants; Apoptosis; Arsenic Trioxide; Arsenicals; Ascorbic Acid; Drug Synergism; Drug Therapy, Combination; Humans; In Situ Nick-End Labeling; Leukemia, Myeloid; Middle Aged; Oxides; Tumor Cells, Cultured

THP-1 cells preferentially accumulate vitamin C in its oxidized form. The uptake displays first-order kinetics and leads to a build-up of an outward concentration gradient which is stable in the absence of extracellular vitamin. The transport is faster than reduction by extracellular glutathione or by added cytosolic extract, and glutathione-depleted cells show the same uptake rates as control cells. In addition, energy depletion or oxidation of intracellular sulfhydryls does not inhibit accumulation of ascorbate. The accumulation, however, always occurs in the reduced form. The affinity for dehydroascorbate is lower (Km 450 microM vs 60 microM) than for reduced ascorbate, but the maximal rate is more than 30 times higher (581 compared to 19 pmol.min-1 per 106 cells), and it is independent of sodium, whereas the uptake of ascorbate is not. The sodium gradient also allows accumulation of reduced ascorbate. Inhibitors of glucose transport by the GLUT-1 transporter also inhibit uptake of dehydroascorbate (DHA), but there are some inconsistencies, because the Ki-values are higher than reported for the isolated transporter and one inhibitor (deoxyglucose) is noncompetitive. The preferential uptake of the dehydro-form of the vitamin may be useful for situations where this short-lived metabolite is formed by oxidation in the environment.

Topics: Ascorbic Acid; Dehydroascorbic Acid; Deoxyglucose; Energy Metabolism; Extracellular Space; Ferricyanides; Glutathione; Humans; Leukemia, Myeloid; Monocytes; Monosaccharide Transport Proteins; Oxidation-Reduction; Reducing Agents; Sulfhydryl Compounds; Tumor Cells, Cultured

Etoposide (VP-16) is extensively used to treat cancer, yet its efficacy is calamitously associated with an increased risk of secondary acute myelogenous leukemia. The mechanisms for the extremely high susceptibility of myeloid stem cells to the leukemogenic effects of etoposide have not been elucidated. We propose a mechanism to account for the etoposide-induced secondary acute myelogenous leukemia and nutritional strategies to prevent this complication of etoposide therapy. We hypothesize that etoposide phenoxyl radicals (etoposide-O(.)) formed from etoposide by myeloperoxidase are responsible for its genotoxic effects in bone marrow progenitor cells, which contain constitutively high myeloperoxidase activity. Here, we used purified human myeloperoxidase, as well as human leukemia HL60 cells with high myeloperoxidase activity and provide evidence of the following. 1) Etoposide undergoes one-electron oxidation to etoposide-O(.) catalyzed by both purified myeloperoxidase and myeloperoxidase activity in HL60 cells; formation of etoposide-O(.)radicals is completely blocked by myeloperoxidase inhibitors, cyanide and azide. 2) Intracellular reductants, GSH and protein sulfhydryls (but not phospholipids), are involved in myeloperoxidase-catalyzed etoposide redox-cycling that oxidizes endogenous thiols; pretreatment of HL60 cells with a maleimide thiol reagent, ThioGlo1, prevents redox-cycling of etoposide-O(.) radicals and permits their direct electron paramagnetic resonance detection in cell homogenates. VP-16 redox-cycling by purified myeloperoxidase (in the presence of GSH) or by myeloperoxidase activity in HL60 cells is accompanied by generation of thiyl radicals, GS(.), determined by HPLC assay of 5, 5-dimethyl-1-pyrroline glytathionyl N-oxide glytathionyl nitrone adducts. 3) Ascorbate directly reduces etoposide-O(.), thus competitively inhibiting etoposide-O(.)-induced thiol oxidation. Ascorbate also diminishes etoposide-induced topo II-DNA complex formation in myeloperoxidase-rich HL60 cells (but not in HL60 cells with myeloperoxidase activity depleted by pretreatment with succinyl acetone). 4) A vitamin E homolog, 2,2,5,7, 8-pentamethyl-6-hydroxychromane, a hindered phenolic compound whose phenoxyl radicals do not oxidize endogenous thiols, effectively competes with etoposide as a substrate for myeloperoxidase, thus preventing etoposide-O(.)-induced redox-cycling. We conclude that nutritional antioxidant strategies can be targeted at minimizing etoposid

Topics: Acute Disease; Antineoplastic Agents, Phytogenic; Antioxidants; Ascorbic Acid; Chromans; DNA Topoisomerases, Type II; DNA, Neoplasm; Electrons; Etoposide; Free Radicals; HL-60 Cells; Humans; Hydrogen Peroxide; Leukemia, Myeloid; Oxidation-Reduction; Peroxidase; Phospholipids; Sulfhydryl Compounds; Vitamin E

Exposure of cells to ionizing radiation can cause apoptosis. Since antioxidants have been shown to protect against radiation-induced apoptosis, in this study we have evaluated the putative protective effect of ascorbate against radiation-induced apoptosis as well as the production of peroxides in the cells. HL60 cells transport the oxidized form of ascorbic acid, dehydroascorbic acid (DHA), and accumulate reduced ascorbate. Exposure of the cells to 5-40 Gy X radiation resulted in induction of apoptosis. Preincubation of the cells with DHA reduced the level of apoptosis after exposure to 5-20 Gy. Exposure of the cells to 5 or 20 Gy X radiation did not affect the intracellular concentration of peroxides, while phorbol myristate acetate (PMA), which is known to induce production of H(2)O(2) in cells (and served as a control), resulted in an increase in peroxides and a decrease in intracellular ascorbate. Irradiation of the cells with 1-3 Gy resulted in up-regulation of expression of BCL2 without affecting the level of apoptosis. At higher doses of radiation, enhanced BCL2 expression did not prevent radiation-induced apoptosis. Loading of the cells with ascorbate prior to their exposure to 1-3 Gy X radiation did not affect the enhanced BCL2 expression observed in the irradiated cells. At higher doses of radiation, ascorbate decreased apoptosis and restored the level of BCL2 in the cells. Exposure of the cells to 3-20 Gy X radiation enhanced the cell surface expression of TNFRSF6 (formerly known as Fas/APO-1) antigen and enhanced anti-TNFRSF6 antibody-induced apoptosis of the cells. Ascorbate loading did not affect expression of TNFRSF6 and did not overcome the anti-TNFRSF6 antibody-induced apoptosis. In conclusion, our data demonstrate that exposure of HL60 cells to radiation enhanced BCL2 and TNFRSF6 expression. Ascorbate did not affect BCL2 or TNFRSF6 expression. We therefore conclude that it protects HL60 cells against radiation-induced apoptosis, although the mechanisms of protection must still be elucidated.

Topics: Apoptosis; Ascorbic Acid; fas Receptor; HL-60 Cells; Humans; Leukemia, Myeloid; Peroxides; Proto-Oncogene Proteins c-bcl-2; Tetradecanoylphorbol Acetate; Up-Regulation; X-Rays

Epidemiological studies have provided evidence that diets rich in antioxidant nutrients may reduce the risk of cancer. To evaluate the possibility that dietary phytochemicals with antioxidant potential would create an environment capable of affecting the differentiation of HL-60 leukemia cells, we measured the effects of vitamin E and other dietary antioxidants on the differentiation produced by low levels of vitamin D3 and analogs thereof. Vitamin E succinate and other antioxidant compounds (ie butylated hydroxyanisole, beta-carotene and lipoic acid) used alone had no significant effect on the differentiation of HL-60 cells; however, these agents markedly increased the differentiation produced by vitamin D3. Previous studies from this laboratory have shown that a sequence-specific antisense phosphorothioate oligonucleotide to the Rel A subunit of NF-kappaB enhanced the differentiation of HL-60 cells produced by several inducing agents. Consistent with these observations, vitamin E succinate caused a marked reduction in the nuclear content of NF-kappaB both in the presence and absence of vitamin D3. These findings suggest that NF-kappaB may be a factor in regulating the differentiation of myeloid leukemia cells. The results also indicate that combinations of vitamin D3 and analogs thereof with dietary antioxidants may be useful in overcoming the differentiation block present in acute promyelocytic leukemia cells.

Topics: Antioxidants; Ascorbic Acid; beta Carotene; Butylated Hydroxyanisole; Cell Differentiation; Cholecalciferol; HL-60 Cells; Humans; Leukemia, Myeloid; NF-kappa B; Thioctic Acid; Vitamin E

Since mice can synthesize ascorbic acid but man cannot, the ascorbate status in murine and human leukaemia was compared. The decline in plasma ascorbate concentration in both cases indicates that vitamin C deficiency occurs in malignancy. Analysis of tissue ascorbate values in mice also indicated that an enhanced rate of utilization of this vitamin occurs during malignancy, as does an increased rate of excretion, and both events may be responsible for vitamin C deficiency. The hepatic ascorbate values suggest an endeavour by the animals to compensate for the loss through increased synthesis and storage of the vitamin, at least in the early stages of the disease.

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Humans; Kidney; Leukemia, Experimental; Leukemia, Lymphoid; Leukemia, Myeloid; Liver; Mice; Spleen; Tissue Distribution

The blood, spleen and liver of RFM/Un mice were examined by means of electron spin resonance (ESR) throughout the course of myeloid leukaemia induced by i.v. injection of leukaemic spleen cells. Marked changes in the concentration of iron transferrin and caeruloplasmin were observed in the blood 1 day after injection. As the disease progressed, changes occurred in the concentrations of the ascorbyl radical and of paramagnetic metal complexes in both spleen and liver. These changes are compared with those induced in RF/J mice injected with normal and leukaemic spleen cells from RFM/Un mice.

Topics: Animals; Ascorbic Acid; Ceruloplasmin; Electron Spin Resonance Spectroscopy; Female; Leukemia, Experimental; Leukemia, Myeloid; Liver; Male; Mice; Mice, Inbred Strains; Organ Size; Spleen; Time Factors; Transferrin

Topics: Adolescent; Ascorbic Acid; Dehydroascorbic Acid; Female; Humans; Leukemia, Myeloid; Leukocytes; Male; Middle Aged

The ascorbyl radical concentration has been observed, by means of electron spin resonance spectroscopy, in the blood, spleen and liver of RF/J female mice throughout the development of a myeloid leukaemia. Changes in the concentration of the radical were detectable from an early stage in the disease and did not appear to be directly due to the leukaemic cells but could possibly be due to a reaction against them. Changes in the concentration of the paramagnetic metal ions during the leukaemia have been reported previously and it was found that changes in some of these species correlated with changes in the ascorbyl radical concentration.

Topics: Animals; Ascorbic Acid; Electron Spin Resonance Spectroscopy; Female; Leukemia, Myeloid; Liver; Mice; Organ Size; Spleen

Topics: Animals; Ascorbic Acid; BCG Vaccine; Leukemia, Myeloid; Leukocytes; Macrophages; Phagocyte Bactericidal Dysfunction; Polycythemia Vera; Rabbits

Topics: Adult; Alcohol Oxidoreductases; Ascorbic Acid; Blood Platelets; Carboxy-Lyases; Child; Erythrocytes; Esterases; Female; Glucuronates; Humans; Ketones; Lactones; Leukemia, Myeloid; Male; Middle Aged; Sugar Acids; Xylitol

Topics: Adolescent; Adult; Alcohol Oxidoreductases; Ascorbic Acid; Busulfan; Carboxy-Lyases; Child, Preschool; Esterases; Female; Glucuronates; Humans; Ketones; Leukemia; Leukemia, Myeloid; Leukocytes; Male; Middle Aged; Pyrophosphatases; Sugar Acids; Uridine Diphosphate Sugars; Uronic Acids; Xylitol

The platelet ascorbic acid concentration was measured in 26 normal subjects and found to be 20 times as high as in plasma. This is in agreement with previous reports in the literature. The platelets of patients with uraemia, leukaemia, and megaloblastic anaemia had a lower than normal platelet ascorbic acid content. In uraemia and megaloblastic anaemia the plasma ascorbic acid concentration was normal suggesting that a platelet defect may be responsible for the low platelet ascorbic acid content. In leukaemia the low platelet ascorbic acid content is probably secondary to a low plasma level.

Topics: Acute Disease; Adolescent; Adult; Anemia, Macrocytic; Ascorbic Acid; Blood Platelet Disorders; Blood Platelets; Female; Humans; Leukemia; Leukemia, Lymphoid; Leukemia, Myeloid; Male; Plasma; Uremia

Topics: Agglutination Tests; Ascorbic Acid; Candida; Candidiasis; Humans; Immunodiffusion; In Vitro Techniques; Iron; Leukemia, Lymphoid; Leukemia, Myeloid; Leukemia, Myeloid, Acute; Lymphoma; Multiple Myeloma; Polycythemia Vera; Precipitin Tests; Transferrin

Topics: Aged; Anemia, Sideroblastic; Ascorbic Acid; Autopsy; Blood Cell Count; Blood Transfusion; Bone Marrow; Bone Marrow Cells; Bone Marrow Examination; Erythrocytes; Erythropoiesis; Folic Acid; Follow-Up Studies; Humans; Hyperplasia; Iron; Leukemia, Myeloid; Male; Middle Aged; Monocytes; Muramidase; Precancerous Conditions; Pyridoxine; Vitamin B 12

Topics: Ascorbic Acid; Chronic Disease; Humans; Leukemia, Lymphoid; Leukemia, Myeloid; Niacinamide; Pyridoxine; Riboflavin; Thiamine; Tryptophan; Vitamin B 12; Vitamin B 6 Deficiency; Vitamins

Topics: Ascorbic Acid; Humans; Leukemia; Leukemia, Myeloid; Liver Cirrhosis; Liver Cirrhosis, Alcoholic; Polycythemia Vera; Vitamin A; Vitamins